/*
 * Copyright &copy; 2010-2011 Rebecca G. Bettencourt / Kreative Software
 * <p>
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * <a href="http://www.mozilla.org/MPL/">http://www.mozilla.org/MPL/</a>
 * <p>
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 * <p>
 * Alternatively, the contents of this file may be used under the terms
 * of the GNU Lesser General Public License (the "LGPL License"), in which
 * case the provisions of LGPL License are applicable instead of those
 * above. If you wish to allow use of your version of this file only
 * under the terms of the LGPL License and not to allow others to use
 * your version of this file under the MPL, indicate your decision by
 * deleting the provisions above and replace them with the notice and
 * other provisions required by the LGPL License. If you do not delete
 * the provisions above, a recipient may use your version of this file
 * under either the MPL or the LGPL License.
 * @since OpenXION 1.2
 * @author Rebecca G. Bettencourt, Kreative Software
 */

package com.kreative.openxion.binpack;

import java.util.Map;

public class DFUnaryExpression implements DFExpression {
	public static enum Operation {
		BOOLEAN_IDENTITY,
		BOOLEAN_NOT,
		BITWISE_NOT,
		IDENTITY,
		ABS,
		NEGATE,
		REVERSE_BITS,
		REVERSE_BYTES;
	}
	
	private Operation op;
	private DFExpression expr;
	
	public DFUnaryExpression(Operation op, DFExpression expr) {
		this.op = op;
		this.expr = expr;
	}

	public int evaluate() {
		switch (op) {
		case BOOLEAN_IDENTITY: return (expr.evaluate() == 0) ? 0 : 1;
		case BOOLEAN_NOT: return (expr.evaluate() == 0) ? 1 : 0;
		case BITWISE_NOT: return ~expr.evaluate();
		case IDENTITY: return expr.evaluate();
		case ABS: return Math.abs(expr.evaluate());
		case NEGATE: return -expr.evaluate();
		case REVERSE_BITS: return Integer.reverse(expr.evaluate());
		case REVERSE_BYTES: return Integer.reverseBytes(expr.evaluate());
		default: return 0;
		}
	}
	
	public int evaluate(Map<?,?> fieldValues, BitInputStream in, long length) {
		switch (op) {
		case BOOLEAN_IDENTITY: return (expr.evaluate(fieldValues, in, length) == 0) ? 0 : 1;
		case BOOLEAN_NOT: return (expr.evaluate(fieldValues, in, length) == 0) ? 1 : 0;
		case BITWISE_NOT: return ~expr.evaluate(fieldValues, in, length);
		case IDENTITY: return expr.evaluate(fieldValues, in, length);
		case ABS: return Math.abs(expr.evaluate(fieldValues, in, length));
		case NEGATE: return -expr.evaluate(fieldValues, in, length);
		case REVERSE_BITS: return Integer.reverse(expr.evaluate(fieldValues, in, length));
		case REVERSE_BYTES: return Integer.reverseBytes(expr.evaluate(fieldValues, in, length));
		default: return 0;
		}
	}
	
	public int evaluate(Map<?,?> fieldValues, BitOutputStream out) {
		switch (op) {
		case BOOLEAN_IDENTITY: return (expr.evaluate(fieldValues, out) == 0) ? 0 : 1;
		case BOOLEAN_NOT: return (expr.evaluate(fieldValues, out) == 0) ? 1 : 0;
		case BITWISE_NOT: return ~expr.evaluate(fieldValues, out);
		case IDENTITY: return expr.evaluate(fieldValues, out);
		case ABS: return Math.abs(expr.evaluate(fieldValues, out));
		case NEGATE: return -expr.evaluate(fieldValues, out);
		case REVERSE_BITS: return Integer.reverse(expr.evaluate(fieldValues, out));
		case REVERSE_BYTES: return Integer.reverseBytes(expr.evaluate(fieldValues, out));
		default: return 0;
		}
	}
	
	public String toString() {
		StringBuffer s = new StringBuffer();
		s.append("(");
		switch (op) {
		case BOOLEAN_IDENTITY: s.append("!!"); break;
		case BOOLEAN_NOT: s.append("!"); break;
		case BITWISE_NOT: s.append("~"); break;
		case IDENTITY: s.append("+"); break;
		case NEGATE: s.append("-"); break;
		default: s.append("<"+op.name().toLowerCase()+">"); break;
		}
		s.append(expr.toString());
		s.append(")");
		return s.toString();
	}
}
